Watch Out for Moon Quakes!

NASA astronauts are going back to the moon and when they function at that place they may need quake-proof housing. Thats the surprising conclusion of Clive R. Neal, associate prof of civil engineering and geological sciences at the University of Notre Dame posterior on he and a team of 15 former(a) fickle scientists reexamined Apollo data from the 1970s. The moon is seismically active, he told a gathering of scientists at NASAs Lunar Exploration Analysis Group (LEAG) meeting in League City, Texas, last October. between 1969 and 1972, Apollo astronauts placed seismometers at their landing sites most the moon. The Apollo 12, 14, 15, and 16 instruments faithfully radioed data back to earth until they were switched come to in 1977. And what did they reveal? There are at least foursome different kinds of moonquakes: (1) deep moonquakes about 700 km below the surface, in all likelihood caused by tides; (2) vibrations from the affect of meteorites; (3) thermal quakes cause d by the expansion of the wintry crust when prime(a) illuminated by the morning sunbathe after ii weeks of deep-freeze lunar night; and (4) alter moonquakes solitary(prenominal) 20 or 30 kilometers below the surface. The first three were largely mild and harmless. Shallow moonquakes on the other hand were doozies. Between 1972 and 1977, the Apollo seismic network saw 28 of them; a a couple of(prenominal) registered up to 5.

5 on the Richter scale, says Neal. A order of order of magnitude 5 quake on Earth is energetic bounteous to move heavy furniture and crack plaster. Further more, alter moonquakes lasted a remarkably long time. Once they got going, all move more than 10 minu tes. The moon was ringing like a bell, Neal ! says. On Earth, vibrations from quakes normally die away in only half a minute. The reason has to do with chemical weathering, Neal explains: pee weakens stone, expanding the structure... If you want to get a full essay, order it on our website: OrderEssay.net

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